Analytical challenges in direct oxidation of l-sorbose

A review of literature concerning direct platinum catalyzed oxidation of l-sorbose reveals great differences in selectivity obtained by different researcher groups. Thus, the question arises whether or not the results reported up to now are comparable at all. In order to clarify this issue, two heterogeneous platinum catalysts known from literature as well as one in-house platinum catalyst were applied in the oxidation of l-sorbose under equal reaction conditions. All samples were analyzed using two different HPLC methods. Selectivity towards 2-keto-l-gulonic acid was determined on the basis of these analytical data. A comparison revealed a great discrepancy between the results, which can be found in relevant publications and the results of this study.